Metallic joist



Nov. 13, 1928.

J. KAHN METALLIC JOIST Filed May 23, 1925 [XI/EN TOR.

Z; ATTORNEY.

Patented Nov. 13, 1928.

UNITED STATES PATENT OFFICE.

JULIUS KAHN, OF YOUNGSTOWN, OHIO, ASSIGNOR 'IO TRUSCON STEEL COMPANY,OI"

YOUNGSTOWN, OHIO, A CORPORATION OF MICHIGAN.

METALLIC JOIST.

Application filed May 23, 1925. Serial N0. 32,496.

The present invention relates to structural elements for buildings andmore specifieally for metallic oists.

Among the objects of the invention is"a light strong rigid joist whichshall have the maximum strength and rigidity for 1ts weight anddimensions.

Another object is the production of such joists in an efficient andeconomical manner so as to reduce'waste as scrap or as unstressed metal.

With these and other objects in view as will readily appear to thoseskilled in the art, the invention consists broadly in a joist fabricatedof sheet metal in the manner and form indicated in the followingdescription and drawings, in which:

Fig. 1 is a plan view of strip of metal showmg how such strip is firsttreated.

Fig. 2 is an elevation of a portion of a finished joist.

Fig. 3 is a section on line 3-3 of Fig, 1.

Fig. 4 is a section on line 4- 1 of Fig. 1.

Fig. 5 is a section on line 55 of Fig. 2.

Fig. 6 is a section on line 66 of Fig. 2.

As indicated in the drawing the joist forming the subject matter of theinvention is produced by starting with a flat strip of metal 10 andcutting along the line 11 to produce two mated strips 12 and 13 eachconsisting of a chord portion 14 with laterally projecting triangularportions 15 spaced from each other and having the apexes of thetriangles integral with the chord portion. Previous to the cuttingoperation or simultaneous therewith or even after the cutting operationthe triangular portion 15 may be ribbed alongthe two sides as at 16 anda small triangular piece of metal may also be removed as at 17. Theremoval of the small triangle lessens the weight of metal in thefinished element but does not materially reduce the strength. The cutout strips so. formed are then placed end to end with one reversed andthe chord portions butt-welded after which an element of I-beam sectionis produced by spot-welding on either side of the chord portion as at'18 an angle iron 20 to form one base and on either side of the bases ofthe triangles as at 19 to form the other base. In order to produce amore rigid supportmg end on the element so formed there may be welded atthe end of the element two small channels 21 as is indicated in Figs. 256 and 6 and these channels allowed to project beyond the lower baseportion produced by welding the angle irons onto the chord portion ofthe web. The channels 21 will be spot-welded to the ends of the angleirons 60 By following the above procedure there is produced a lightstrong building element which has the maximum strength for the weight ofmetal used and which may be produced economically because of the smallwaste of metal.

Having now described the invention and the preferred embodiment thereof,it should be understood that it is not to be limited to the precisedetails given but is to be limited pnly by the scope of the claims whichfol- I claim 1'. A 'metallic joist consisting of a sheet '76 metal webportion cut out to form a chord portion with spaced triangular portionsprojecting laterally therefrom with their apexes integral with saidchord portion, and having flat upper and lower surfaces formed bywelding angle irons to the sides of said chord portion and to the sidesof the bases of the triangles. v

2. A metallic joist consistin of a sheet metal web portion cut out toorm a chord s5 portion with spaced triangular portions pro-' j ectinglaterally therefrom with their apexes integral with said chord portion,and having fiat upper and lower surfaces formed by welding angle ironsto the sides of said chord portion and to the sides of the bases'of thetrian les and also having extended supporting c 0rd portions formed ofnarrow channel members welded back to back and to the bases of the endtriangles and'made continu- .95 ous with the upper angle irons bybuttwelding.

3. A metallic joist consisting of an I- beam having a web of sheet metalcut out to form a narrow continuous chord portion with spaced triangularweb portions having a narrow continuous chord portion with their apexesintegral with the Chord portion, spaced laterally extending bars, theweb havthe Web having base members welded to the ing base members weldedto the chord porlo chord portion and to the bases of the trition and tothe outer extremities of said 5 angles. bars.

. 4. A metallic 'oist consisting of an I-beam having a web of sheetmetal cut out to form JULIUS KAI-IN,-

